The use of the optical theorem and the operator product expansion leads to a theoretical prediction for the decay width, and hence lifetime, for each \(b\) -flavored hadron [1]}
\(\Gamma =&\frac{G_F^2m_b^5}{192\pi ^3}\left|V_{cb}\right|^2\left\lbrace c_{3,b}\left[1-\frac{\mu _{\pi }^2-\mu _{G}^2}{2m_b^2}+{\cal {O}}\left(\frac{1}{m_b^3}\right)\right] \right. \nonumber \\&+\left. 2c_{5,b}\left[\frac{\mu ^2_G}{m_b^2}+{\cal {O}}\left(\frac{1}{m_b^3}\right)\right]+\frac{c_{6,b}}{m_b^3}\frac{\langle B|(\overline{b}q)_{\Gamma }(\overline{q}b)_{\Gamma }|B\rangle }{M_B}+...\right\rbrace .\) 
